题解 | #牛群编号的回文顺序#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param head ListNode类
     * @return bool布尔型
     */
    public boolean isPalindrome (ListNode head) {
        // write code here
        ArrayList<Integer> list = new ArrayList<>();
        while (head != null) {
            list.add(head.val);
            head = head.next;
        }
        int mid = list.size() / 2;
        int i = 0, j = list.size() - 1;
        while (i < j) {
            if (list.get(i) != list.get(j)) {
                return false;
            }
            i ++;
            j --;
        }
        return true;
    }
}